Brakes - Front - Brembo HC Discs, DS2500 Pads, Braided Lines all round, Dot 5 Fluid, Rears - leave standard... Parts cost £220-£230.
Suspension - Eibach Prolines or Sportlines "Sport for show, Pro for go"... Prolines are stiffer and lower 20mm, better handling, Sportlines lower 30-40mm but can be a bit "crashy" - Parts Cost £140. Standard Shocks are OK with these, but standard rears are prone to leaking (£50 each to replace, but thats just wear & tear)
RS Tuner - Chip Your Own Car. £150 (Smoother/improved torque)
Exhaust - Multiple Options here, opinions devided depending on what you want from a system, decat etc... £300+
Air Filter - Ph1 (V6) Airbox system is well regarded - Check out JMS Tuning's Page on here - £160.
Matched Inlets - £100+...
All in all small gains, your not going to see 200bhp without going to ITBs, SC or Turbo.
And a free mod = Strippage.